The present invention relates to aircraft; and more particularly, the invention relates to the wing construction of an aircraft.
Modern aircraft are equipped with wings having leading edge slats which are advanced during takeoff and landing for increasing the lift. They are also termed "high-lift devices." These leading edge slats are provided, for example, with arc-shaped rails engaging guide elements, such as rolls, mounted on the wing. The slats can be moved into the desired position under utilization of a suitable drive which may include a gear spindle in each instance.
It was found that this type of guiding and drive system for leading edge slats poses problems. For example, the drive spindles are quite long. They project deeply into the wing when the slats are retracted. This complicates the wing construction because the interior of the wing is occupied to a large extent by the fuel tanks. The tanks, of course, must be kept separated from tubular sheats receiving the spindles. Moreover, these spindles are driven by means of transmission gears. The spindle pitch differs with distance from the fuselage in order to obtain a constant gap width between the slat and the remainder of the wing.
Another version for such leading edge wing slats and their drive and moving mechanism is disclosed in German printed patent application No. 23,55,723. The device as described therein includes pivot drives for two leading edge slats per wing. The slats are positioned and moved by means of cranks, but without direct forward component of movement as in the case of a rail system. In particular, one slat is just pivoted about a fixed pivot point on the wing case, and another slat is folded up having a pivot point on the first slat. As a consequence, lift is augmented by such a slat arrangement to a minor extent only because the overall advance of the slat is smaller. Actually, the advance is the result of employing two slats, whereby pivoting the inner slat advances to a minor extent the pivotal point of the second slat.
The particular drive system disclosed in the publication is not suitable for actually advancing the leading edge slat out of the main wing case.